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Electrochemical Deposition of Silver on Aluminum Alloys

Valov R., Petkov V., Valkanov S.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

101--104

EN

Silver coatings have a very high reflection ability. To avoid their darkening from the hydrogen sulphide in the air, a thin layer of heat-resistant colorless lacquer is applied to the coatings. Silver plating is mainly used in jewelery, optics, electronics and electrical engineering. Depending on their application the thickness of the layer may vary from 2 to 24 μm. It can be done in several ways: chemical, electrochemical, contact, etc. The most common way of silver plating is the electrochemical deposition using cyanide and non-cyanide electrolytes. The cyanide electrolytes produce light, fine crystalline, dense and plastic coatings upon silver-plating. Usually silver coatings are applied with copper or nickel intermediate layer. In order to improve the de-oxidation of the aluminum surface new chemical treatment in acid – alkaline solution was applied. Our previous research shows that the presence of diamond nanoparticles in the electrolyte increase the metal deposition. Samples were prepared from electrolyte containing 10 g/l diamond nanoparticles. Their properties were compared to the properties of reference samples. The diamonds were obtained by detonation synthesis. The aim of this study is to obtain electrochemically deposited silver layer with high density, adhesion and electric conductivity on aluminum alloys substrate. The coating was directly plated without intermediate layer. Non-cyanide electrolyte composition and electrochemical parameters were determined in order to produce Ag coatings on Al alloy substrate without intermediate layer. The coating is with good adhesion, density and thickness of 14-23 μm.

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Characteristics and Properties of Chromium Coatings with Diamond Nanoparticles Deposited Directly on Aluminum Alloys

Petkov V., Valov R., Simeonova S., Kandeva M.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

115--120

EN

The objective of this study was to deposit directly chromium with diamond nanoparticles (ND) on aluminum alloys and investigate the coating surface. The chromium coatings on aluminum alloys were obtained by electrochemical deposition. The coatings were doped with ND. The diamond nanoparticles were obtained by detonation synthesis. Chromium coatings were deposited on aluminum alloys with a silicon content of 7 % and 10 %. The ND concentration in the electrolyte was 25 g/l. The surface analysis was performed by means of Atomic force microscopy. The surface of the coating of chromium with ND on Al10Si is twice more even than that on Al7Si. The microstructure and microhardness were examined with a metallographic microscope and a microhardness tester. The microhardness of the coated samples is 9163 MPa compared to 893 MPa of uncoated aluminum samples. The thickness of the chromium coatings doped with diamond nanoparticles is between 45 – 55 μm. The coatings are dense, continuous and uniform with good adhesion to the substrate material.

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Effect of non-modified and modified nanodiamond particles by Fenton reaction on human endothelial cells

Solarska K., Gajewska A., Skolimowski J., Woś R., Bartosz G., Mitura K.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 2

603--607

EN

Purpose: The use of carbon nanoparticles in medicine is increasing due to their high biocompatibility. Nanopowders are one of the best materials which can be used in medicine on medical implants and surgical tools. DPP (Diamond Powder Particles) obtained by different methods which can be expected to affect their properties, including biocompatibility, were compared. The aim of the present study was to compare the biocompatibility of Diamond Powder Particles (DPP) obtained by detonation method and graphite on the basis of their interactions with human endothelial cells. Design/methodology/approach: The effect of nanodiamonds on cell proliferation HUVEC-ST and production of reactive oxygen species (ROS) and reactive nitrogen species (RNS) was studied. We used FT-IR Spectroscopy attributive chemical function groups. Findings: In this subject the material characterization of nanodiamond powders and influence on endothelial cells. Practical implications: Biological research with endothelial cells and nanodiamond powder are the introduction to application in human’s treatment. Originality/value: Nanodiamond powders with chemical modified surface.